Calcium Sulfate

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calcium sulfate

[′kal·se·əm ′səl‚fāt]
(inorganic chemistry)
CaSO4 A white crystalline salt, insoluble in water; used in Keene's cement, in pigments, as a paper filler, and as a drying agent.
Either of two hydrated forms of the salt: the dihydrate, CaSO4·2H2O, and the hemihydrate, CaSO4·½H2O.

Calcium Sulfate

 

CaSO4, a salt, existing in nature as the dihydrate CaSO4-2H2O (gypsum, selenite) and in an anhydrous state (anhydrite). Anhydrous calcium sulfate occurs in the form of colorless crystals with a density of 2.96 g/cm3 and a melting point of 1450°C. It combines very slowly with water, exhibiting a poor solubility of 0.2036 g per 100 g H2O at 20°C and 0.067 g at 100°C. The half-hydrate CaSO4-1/2 H2O is known; when mixed with water, it hardens rapidly, converting into CaSO«2H2O. Calcium sulfate is used in the manufacture of figures and casts, as a construction material, and in medicine.

calcium sulfate

Anhydrite or gypsum dihydrate which has been calcined to the point at which all the water of crystallization has been removed.
References in periodicals archive ?
Reynolds; Clinical evaluation of calcium sulphate in combination with demineralised freeze Dried bone alloplast for the treatment of human intraosseous defects; J Periodontol; 75; 340-47;2004.
In industrial phosphoric acid plants, the concentrated phosphoric acid solution is supersaturated with respect to calcium sulphate. As a result, part of the calcium sulphate in the liquor deposits on the heat exchanger tube walls.
Line of fillers and functional pigments includes clays (water-ground kaolins and bentonites), mica (muscovite and biotite), barytes (natural white and off-white grades), calcium sulphate, calcium carbonate, and the Polytal series of platy talcs designed specifically for polyolefins.
The Finnish chemical industry group Kemira Oyj said today (19 December) that its subsidiary Kemira Chemicals Oy would increase its calcium sulphate pigment production by investing EUR5m into expansion of its pigment plant in Siilinjarvi, Finland.